linq查询以c＃mvc中的聚合和普通列

Question

I have two tables fooditem(itemid,itemname,itemprice) and another rating(itemid,vote,itemid,username)

How to get sum of votes groupby itemid in rating table and the itemname ,itemprice corresponding to the total rating on each food item. sql query is

select table2.sum(votes),table1.itemname,table1.itemprice from table1,table2 where table1.itemid==table2.itemid group by table2.itemid

I started with this query.Bad luck!

    List<FoodView> items= (from a in db.FoodItems 
                                   join b in db.Ratings on a.itemid equals b.itemid
                                   group b by  b.itemid into g

                                   select new FoodView
                                   {
                                    itemname=g.Select(d=>d.itemname),
                                    itemprice=g.Select(d=>d.itemprice),
                                    vote=g.Sum(d=>d.vote)
                                   }).ToList();

FoodViewModel vm = new FoodViewModel { Foodviews= items};

My Model is

  public class FoodViewModel
{
    public List<FoodView> Foodviews { get; set; }

    public FoodViewModel()
    {
        Foodviews = new List<FoodView>();
    }
}

public class FoodView
{
    public long? itemid { get; set; }
    public string itemname { get; set; }

    public long? itemprice { get; set; }

    public long? vote { get; set; }

}

Answer 1

Please use following query:


 var foodViewsList = (from t in fooditems
                         join r in ratings on t.itemid equals r.itemid
                         group r by new { r.itemid, t.itemname, t.itemprice } into g
                         select new FoodView
                         {
                             itemid = g.Key.itemid,
                             itemname = g.Key.itemname,
                             itemprice = g.Key.itemprice,
                             vote = g.Sum(x => x.vote)
                         }).ToList();